Correct Answer: (3) Mahendragarh
Solution:Mahendragarh district is richest in mineral resources in Haryana, though Ambala, too, is well endowed. Some of the mineral resources of Mahendragarh are limestone, quartz/silica sand, slate, barytes, calcite, felspar, marble, copper, dolomite, etc. Haryana is the principal holder of country's resources of tin (64%), quartasilica sand (52%) and quartzite (49%).